 public class Example4_5  {       

   public static void main(String args[]) {

      Rect ractangle = new Rect();

      ractangle.width = 109.87;

      ractangle.height = 25.18;

      double area=ractangle.getArea();

      System.out.println("矩形的面积:"+area); 

      Lader lader=new Lader();

      lader.above=10.798;

      lader.bottom=156.65;

      lader.height=18.12;

      area=lader.getArea();

      System.out.println("梯形的面积:"+area); 

    }

}
